multiset
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A container that is optimized for
fast associative lookup. Items are matched using the operator==
. When an item is inserted into a multiset , the
item is stored in a data structure where it can be found quickly. Within the
data structure, the items are ordered according to a user-defined comparator
function object. A typical user-supplied function object is less, which orders
the items in ascending order. Unlike a set , a multiset
can contain multiple copies of the same item.
Library
Standards<ToolKit>
Declaration
#include <set>
template< class T, class Compare, class Allocator >
class multiset
Interface
Constructor
multiset()
Constructs an empty
multiset that orders elements using the comparator Compare()
and manages storage using Allocator() .
Constructor
explicit
multiset( const Compare& compare ,
const Allocator& alloc )
Constructs an empty
multiset that orders elements using the comparator compare
and manages storage using alloc (default Allocator()
).
Constructor
multiset(
const T* first ,
const T* last ,
const Compare& compare ,
const Allocator& alloc )
Constructs a multiset
that contains copies of the elements in the range
[ first ,
last ) , using
compare (default Compare()
) to order the elements, and using alloc (default Allocator()
) to manage storage.
Constructor
multiset(
const_iterator first ,
const_iterator last , const
Compare& compare , const
Allocator& alloc )
Constructs a multiset
that contains copies of the elements in the range
[ first , last
) , using compare
(default Compare() ) to order the elements, and
using alloc (default Allocator()
) to manage storage.
Constructor
multiset(
const multiset< T, Compare, Allocator >& other
)
Constructs a copy of other
.
Destructor
~multiset()
Destroys the multiset and
erases all of its items.
=
multiset<
T, Compare, Allocator >& operator=( const multiset< T, Compare,
Allocator >& other )
Replaces the contents of
the multiset with a copy of other .
begin
iterator
begin()
Returns an iterator
positioned at the multiset's first item.
begin
const_iterator
begin() const
Returns a constant
iterator positioned at the multiset's first item.
clear
void
clear()
Erases all of the
multiset's elements.
count
size_type
count( const T& value )
const
Returns the number of
elements multiset contains that match value .
empty
bool
empty() const
Returns true
if the multiset contains no entries.
end
iterator
end()
Returns an iterator
positioned immediately after the multiset's last item.
end
const_iterator
end() const
Returns a constant
iterator positioned immediately after the multiset's last item.
equal_range
pair<
iterator, iterator > equal_range( const T& value
)
Returns a pair of
iterators with a first element that is equal to lower_bound()
and a second element that is equal to upper_bound()
.
equal_range
pair<
const_iterator, const_iterator >
equal_range( const T& value )
const
Returns a pair of
iterators with a first element that is equal to lower_bound()
and a second element that is equal to upper_bound()
.
erase
void
erase( iterator pos )
Erases the element at pos
.
erase
void
erase( iterator first ,
iterator last )
Erases elements in the
range [ first , last
) .
erase
size_type
erase( const T& value )
Erases all elements that
match value and returns the number of elements
erased.
find
iterator
find( const T& value )
If the multiset contains
an element that matches value , returns an
iterator positioned at the matching element. Otherwise, returns an iterator
positioned at end() .
find
const_iterator
find( const T& value )
const
If the multiset contains
an element that matches value , returns an
iterator positioned at the matching element. Otherwise, returns an iterator
positioned at end() .
get_allocator
Allocator
get_allocator() const
Returns a copy of the
allocator used to manage storage.
insert
iterator
insert( const T& value )
Inserts a copy of value
and returns an iterator positioned at the new element.
insert
void
insert( const T* first ,
const T* last )
Inserts copies of the
elements in the range [ first
, last )
.
insert
void
insert( const_iterator first ,
const_iterator last )
Inserts copies of the
elements in the range [ first
, last )
.
insert
iterator
insert( iterator pos ,
const T& value end()
.
lower_bound
const_iterator
lower_bound( const T& value )
const
Returns a constant
iterator positioned at the first location value could
be inserted without violating the ordering criteria. If no such location is
found, returns a constant iterator positioned at end()
.
max_size
size_type
max_size() const
Returns the maximum
number of entries the multiset can contain.
rbegin
reverse_iterator
rbegin()
Returns a reverse
iterator positioned at the multiset's last item.
rbegin
const_reverse_iterator
rbegin() const
Returns a constant
reverse iterator positioned at the multiset's last item.
rend
reverse_iterator
rend()
Returns a reverse
iterator positioned immediately before the multiset's first item.
rend
const_reverse_iterator
rend() const
Returns a constant
reverse iterator positioned immediately before the multiset's first item.
size
size_type
size() const
Returns the number of
entries the multiset contains.
swap
void
swap( multiset< T, Compare, Allocator >& other
)
Exchanges the contents of
multiset and other .
upper_bound
iterator
upper_bound( const T& value )
Returns an iterator
positioned at the last location value can be
inserted without violating the ordering criteria. If no such location is
found, returns an iterator positioned at end()
.
upper_bound
const_iterator
upper_bound( const T& value )
const
Returns a constant
iterator positioned at the last location value can
be inserted without violating the ordering criteria. If no such location is
found, returns a constant iterator positioned at end()
.
value_comp
Compare
value_comp() const
Returns the comparison
object.
Non-Member Functions
==
bool
operator==( const multiset< T, Compare, Allocator >& x
, const multiset< T, Compare,
Allocator >& y )
Returns true
if x contains the same items in the same order as y
.
<
bool
operator<( const multiset< T, Compare, Allocator >& x
, const multiset< T, Compare,
Allocator >& y )
Returns true
if x is lexicographically less than y
.
swap
void
swap( const multiset< T, Compare, Allocator >& x
, const multiset< T, Compare,
Allocator >& y )
Exchanges the contents of
x and y .
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